Purge enclosure for electrical equipment in hazardous location

Abstract

A protective or purge enclosure provides a positive atmosphere around an operating device such as a hand-held computer or calculator contained therein. The protective enclosure has sufficient flexibility, even though providing a positive, sealed atmosphere, to enable the user to operate the functional features of the device sealed within the enclosure, and the material forming the device is sufficiently transparent to enable the user to view the functional features of the device for operation. A visible indicator provided on the enclosure enables the user to determine if the enclosure is maintaining the positive atmosphere sealed therein.

I claim: 
     
       1. A protective, sealable enclosure capable of maintaining an atmosphere therein which is positive relative to the atmosphere outside the enclosure and separate therefrom, said enclosure being formed of a flexible material sufficiently transparent to enable a user to view a manually operable device, when sealed therein, and the functional features associated with such device, the balance between the positive atmosphere within the sealed enclosure and the flexible material forming the enclosure permitting manual operation of the device, while said enclosure retains said positive atmosphere therewithin, said enclosure including a balloon connected to the enclosure so as to have the same positive pressure as the positive pressure of the enclosure, said balloon being inflated to the same positive atmosphere as the atmosphere within the sealed enclosure and thereby being capable of indicating a change in the pressure retained by the enclosure. 
     
     
       2. A protective, sealable enclosure as claimed in claim 1 wherein said enclosure is unanchored and free of any connection to adjacent fixed members with said enclosure. 
     
     
       3. A protective, sealable enclosure with a manually operable device sealed therein, said enclosure being capable of maintaining an atmosphere therein which is positive relative to the atmosphere outside the enclosure and separate therefrom, said enclosure being formed of a flexible material sufficiently transparent to enable a user to view said manually operable device sealed therein and the functional features associated with such device, the balance between the positive atmosphere within the sealed enclosure and the flexible material forming the enclosure permitting manual operation of the device while said enclosure retains said positive atmosphere therewithin, said enclosure including a balloon connected to the enclosure so as to have the same pressure as the positive pressure of the enclosure, said balloon being inflated to the same positive atmosphere as the atmosphere within the sealed enclosure and thereby being capable of indicating a change in the pressure retained by the enclosure. 
     
     
       4. The combination according to claim 3 in which said manually operable device is a self-contained hand-held instrument having a pushbutton keyboard.